Sprocket wheel and tooth therefor



Dec. 12, 1950 w, J, URBAN 2,534,187

SPROCKET WHEEL AND TOOTH THEREFOR Filed Feb. 8, 1947 -J2U6f2f0r- *0/27 MZZz'amJUran.

Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE SPROCKET WHEEL AND TOOTH THEREFOR William J. Urban, Glen Ellyn, Ill., assignorto American Ore Reclamation Company, Chicago, 111., a corporation of New York Application February 8, 1947, Serial No. 727,331

3 Claims.

This invention relates, generally, to large-sized sprocket wheels of the type adapted for use in elevating pallets at the return bend of a Dwight & Lloyd sintering machine. The invention has particularly relation to such sprocket wheels wherein the projecting teeth are removable, and are secured to the rim of each whee1 by means of shear bolts.

Continuous type sintering machines, such as those of the Dwight 8: Lloyd type, are now well known in the art. In such machines, a train of pallets travel along an endless track having upper and lower runs with return bends at opposite ends. The pallets pass down one return end from the upper run to the lower run under the force of gravity. At the opposite (feed) end it is usual to provide a pair of sprocket wheels secured to the opposite ends of a shaft and so arranged that the projecting teeth of the sprocket wheels serve to elevate the pallets from the lower run to the upper run.

When a sintering machine is operating properly, the teeth on the sprocket wheels enter into spaces provided therefor between the wheels or rollers on the sides of the pallets and engage against bearing surfaces whereby each pallet is propelled and elevated around the return end of the machine so as to place it at the beginning of the upper or feed run. The machine is so designed that each successive tooth on a sprocket wheel engages the next pallet in line and elevates it to the upper run in the same manner. It sometimes happens that as the leading pallet on the return or lower track comes under the sprocket wheels for elevation, it is so positioned that it is not properly aligned for engagement by the sprocket teeth. When this happens the sprocket teeth strike the pallet at some intermediate point of the frame, usually with the result that either the pallet or the sprocket whee1 is broken, or the machine is otherwise damaged. In any event, the machine will have to be temporarily shut down for repairs thus stopping production and involving considerable loss in time.

The object of the present invention is to provide the sprocket wheels with removable teeth which are secured thereto by means of shear bolts, or the equivalent, so that when a tooth strikes against a pallet frame the bolts will shear off, thereby preventing breakage of either the pallet, tooth or sprocket wheel.

Another object of the invention is the provision of sprocket wheels of the type described which are provided with removable teeth so that as one side of a tooth becomes worn in use, the

2 tooth can be reversed so as to wear the opposite side.

Still another object of the invention is the provision of a sprocket wheel of the type described wherein the removable teeth are secured in dovetailed pockets on the rim of the wheel so as to prevent a tooth from falling oil the wheel when the shear bolt by which it is secured is sheared oiI.

Other objects of the invention will, in part, be obvious and will in part appear hereinafter.

For a more complete understanding of the nature and scope of this invention, reference may now be had to the following detailed description of the two presently preferred embodiments thereof, taken in connection with the accompanying drawings, wherein:

Figure l is a diagrammatic, side elevational view of the feed end of a continuous type sintering machine of the Dwight & Lloyd type, provided with sprocket wheels for elevating the pallets, which sprocket wheels have projecting teeth secured thereto in accordance with the present invention;

Figure 2 is a fragmentary, side elevational view of a portion of a sprocket wheel having a removable tooth secured thereto and illustrating one preferred embodiment of the invention;

Figure 3 is an enlarged sectional view taken on line 33 of Figure 2;

Figure 4 is an enlarged sectional view taken on line 4-4 of Figure 2; and

Figure 5 is a sectional view corresponding to Figure 4 but showing a modification wherein the removable tooth and the receiving pocket therefor on the wheel rim are dove-tailed in shape.

Referring first to Figure l of the drawings, the feed end of a continuous type sintering machine, such as the Dwight & Lloyd type of sintering machine, is indicated generally at H]. In accordance with the usual construction, a track H is provided which serves as the upper run of the machine, while a track I 2 serves as the lower run.

A train of pallets 13 are moved along the upper track with the pallets l3 abutting against each other so as to provide a closed supporting area. After the pallets 53 have traversed the upper run from left to right, they are returned by way of the track [2 in an inverted position, as shown. The lower track I2 is provided with an upward bend at [4 so as to provide a decline l5 down which the inverted pallets l3 roll so as to be picked up by a pair of sprocket wheels l5 and returned to the upper run ll.

When the sintering machine H} is working properly, the return pallets It will be fed down the incline l one after the other so that the teeth H on the sprocket Wheels 16 will fit into a pocket between the rollers on each side of the pallets and lift the pallets around the return bend and onto the feed end of the upper run or track l l. The pallets is are filled from a feed. hopper I8 and the contents are then ignited'by the igniter 2%. As the pallets it pass down the track H, the suction boxes 2! draw air therethrough so as to bring about a sintering of the;

pallet contents.

Occasionally, trouble will develop so that. the

inverted pallets E3 do not properly feed downthe decline of the lower run 52. This difficulty is usually caused by sintered material falling on the track l2. However, it may be due to other reasons. In such instances, the teeth I! do not properly interfit within the space provided be- Reference may now be had to Figures 2 through 5; of the drawings. for a more detailed description of the sprocket teeth lland: the manner in which thesame; are sec-uredto the rims 2 2 of the sprocket wheels E6, The sprocket wheels it are usually made in two castings which-are suitablybolted together; wheelis provided with a'number of equally spaced pockets so as to receive: the lower or base. portions of the teeth ll. Preferably, the pockets are 10- catedzmidw-ay between the spokes of each wheel ltrand-are formed by integral flanges 23 which are parallelwith each other. Each pocket is open at opposite ends. The back or floor of each pocket is formedby the central web 24 of the rim 22.

Each tooth ll sits fairly snugly between the sides 230i each pocket. and is secured tothe rim 22. by a pair of shear bolts. 25 which extend throughbosses 26 formedonthe teeth IT. and through the web 2 of the rim.2.2. The shear bolts 25 are preferably formed cfsoft. iron, or equivalent. metal, whiehis softer thaneither the teeth I! or the rim 22.

It isdesirable to provide aneye 2'! throughthe projecting end of each tooth ll. so that it may receive ahook whereby each tooth may be easily recovered when it has been knocked out of place.

When a tooth ll strikes improperly against. a

part. of a pallet i3, the shear bolts 25-will shear off, and-allow the. toothl l to be pushedinward-ly through the pockets, thereby preventing break: age; The sinteringmachine can then be stoppedand the trouble corrected w-ithout'requ-iringany repair other than the replacement of theshear bolts 25.

Rivets, could be used inplaceofthe shear bolts 25. However, thebolts are-more convenient for this-purpose.

In Figure- 5 0i the drawi-ng'a modification-is shown which. serves tofacilitaterecovery of a toothonce it has. beenpushed out of-place. As

thereshown, the-integral. flanges 2-3 forming thesides-of the, teeth receiving pockets are undercut so. asto receive the projectingflanges 28 pro- V'ided on the back sidesof the; teeth I1. Inthis way, each tooth ll" interfits in apocket in a-dove- One side of the rim of each 1 tailed relationship. When the shear bolts 25 holding one of the modified teeth H are sheared off, the tooth can only be pushed inwardly towards the center of the wheel, but cannot fall oif from it.

It will be noted that the teeth I? (Figures 2, 3 and 4) are symmetrical so as to permit each tooth to be reversed on either of the pair of sprocket wheels i6, thereby making it possible to obtain full wear on both pallet engaging surfaces of each tooth. However, the modified teeth l1 (Figure 5) which are provided with retaining flanges 2% cannot be reversed on the same sprocket'wheel l6. However, full wear of these teeth can be obtained of both contact surfaces by transferring one of them to the other sprocket wheel.

The particular shape of the pallet contacting surfacesof the teeth I? and I1 forms the subject matter of my co-pending application Serial No. 723,619 filed Jan. 22, 1947..

Since certain further changesgmay be made in the foregoing embodiments of the invention, and difierent. embodiments may be provided without departingtherefrom, it is intended that all matter described above or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim 1.. In a sprocketv wheel of the character described, a rim having tooth receiving pockets opening,- radially outward thereof,v sprocket teeth mounted; in saidpockets, and shear members restraining said teeth against movement inwardly -of said pockets, said teeth being adapted for movement.radially'inwardly of said pockets upon failure of said shear members under pressure applied. to the outer ends of said teeth and said pockets being unobstructed and open at their inner ends for such inward movement of said teeth responsive to failure of said shear mem-- vided withside flanges and opening radially outward of said rim, sprocket. teeth mounted in said pockets between said flanges thereof, and shear boltssecuring said teeth to said rim, said teeth being. otherwise free for movement radially inwardof said pockets and the latter beingunobstructed at their radially inner ends. for inward movement of saidteeth upon failure of said bolts under pressure appliedto the outer ends of said teeth.

3. In a sprocket wheel of the character described, a. rim. having tooth receiving pockets provided. with undercut side flanges and opening radially outward of said rim, sprocket teeth mountedin said pockets providedwith elements having interfitting frictional engagement. with said flanges, said pockets being open at, their radially inner ends for inward movement of said teeth, and shear bolts securing said teeth to said rim.

WILLIAM J. URBAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS.

Number Name: Date 605,443 Cooper June 7, 1898 1,630,313: Rorabeek May 31, 1927 1,921,329v Smoot Aug; 8, 1933 

